When you laugh while being tickled, what you are experiencing is actually a form of panic.
If you’re ticklish, you know the automatic laugh response that occurs when you are tickled. This can range from giggling to uncontrollable shrieks of laughter. However, your body is actually responding with panic and anxiety.
This is actually the body’s defense mechanism. It is believed that the response is meant to protect you from dangerous things on your skin, such as poisonous insects. The body needs to react quickly to this unanticipated touch and does so with a panic response.